This invention relates to a shock absorbing bumper for vehicles, and more particularly to such a bumper as made mainly of plastic material.
Various types of shock absorbing bumpers made of synthetic resin material have heretofore been proposed, for instance in U.S. Pat. Nos. 4,134,610 to Lindewall and 3,666,310 to Burgess et al. However, many of those conventional bumpers are of such a construction as does not permit production by continuous extrusion molding, resulting in a high manufacturing cost. Further, many of the conventional plastic or rubber made shock absorbing bumpers are common in such a basic idea that the major impact forces imposed on a vehicle bumper are absorbed mainly by the elastic property of an employed specific material such as foamed polyurethane or rubber, or by cushioning effect of fluid confined in an elongated chamber or a tube disposed within a bumper body, as disclosed, for example, in U.S. Pat. Nos. 3,690,710 to Curran, 3,829,141 to Igwe, 3,734,557 to McKenzie, and 3,938,840 to Haase et al in addition to the above referred U.S. Pat. Nos. 4,134,610 and 3,666,310. However, the idea of the present invention is distinguishable from the afore-discussed conventional idea in such a point that shock absorption is attained mainly by a specific, internal mechanical structure of a bumper body.
Accordingly, an object of the present invention is to provide a shock absorbing bumper formed mainly of synthetic resin material by continuous extrusion molding.
Another object of the invention is to provide a shock absorbing bumper which has an outer layer of synthetic resin material and an internal central bumper portion which includes a plurality of axial bores and web portions.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in connection with the accompanying drawings; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.